Torque governor



N. W. STORER TORQUE GOVERNOR March 10, 1931.

Filed Oct. 20, 1927 2 Sheets-Sheet 1 6 2 35 3:9 1 s z 4 5/1 4 M M 3 DU.4 7 5 4 a A w 8 3 HNVENTOR Norman W Sforer.

ATTORNEY Patented Mar. 10, 1931 UNITED STATES PATENT OFFICE ELECTRIC &MANUFACTURING COIVIPANY,v A CORPORATION OF PENNSYLVANIA TORQUE GOVERNORApplication filed October 20, 1927.

This invention relates generally to governors and more particularly toelectrically operated governors for power units.

11 operating busses or railway vehicles propelled by gas-electric oroil-electric power units, when the load is changed, as, for example,when a grade is encountered, the propelling motors tend to maintain theveiicle speed and to draw more current from the enerator, therebyincreasing the generator output and the torque on the generator shaft.The load on the engine, accordingly, will be increased and, unless somemeans is provided for limiting it, the engine will reach its capacitybefore the flexible electrical app-aratus, and will be reduced in speedand its output correspondingly lowered.

It is, therefore, desirable to provide a governor that may be utilizedwith gas-electric and oil-electric power units which will func tion overa wide range of engine speeds to limit the torque that may be requiredfrom the engine. In order to restrict the loading of an engine,different methods may be utilized and, in gas-electric andoil-electrical power systems, it has been found very satisfactory tocontrol the output of the generator and, therefore, to maintain asubstantially constant torque on its drive shaft. Since the inventiondescribed hereinafter relates to a device adapted to maintain asubstantially constant torque on a generator shaft, it will be rercrredto as a torque governor.

The object of the invention, generally stated, is to provide a torquegovernor which shall be simple and efficient in operation and readilyand economically manufactured.

A more specific object of the invention is to provide means formaintaining the output of an engine of an oil-electric power unitsubstantially constant for a predetermined engine sneed, yet permi tingwide variations in armature current and voltage.

A further object of the invention is to provide a means for controllingthe torque imposed by a generator on an internal-combustion or otherengine at a substantially constant value, i respective of the speed, andpermitting a wide variation of the generator curr nt and armatureamperes.

field Serial No. 22 7,460.

Another object of the invention is to provide for adjusting the torquegovernor to function at predetermined torque values in response to thecurrent flow in the field and armature windings of a generator.

It is also an object of the invention to provide for adjusting thegovernor to match its characteristic curve with the characteristic curveof the generator.

The invention, accordingly, as shown in the accompanying drawing,comprises the structural features, combination of elements andarrangement of parts that will be exemplified in the structurehereinafter set forth, and the scope of the application of which will beindicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference may be had to the following detailed description, taken inconjunction with the accompanying drawing, in which;

Figure 1 is a view, partly in section and partly inside elevation, of atorque governor constructed in accordance with this invention,

Fig. 2 is a view, in end elevation, of the torque governor illustratedin Fig. 1,

Fig. 3 is a view, in side elevation, of a ratchet device suitable for atorque governor,

Fig. 4 is a diagram illustrating characteristic curves of generators ofa type suitable for use in Diesel-electric-power units,

Fig. 5 is a diagram showing a series of characteristic curves plottedfrom a test made on a torque governor, to show the effect of varying thespring tension,

Fig. 6 is a diagram illustrating how the torque governor curve may bedistorted by rotating the armature to different positions relative tothe field windings,

Fig. 7 is a diagram illustrating how the torque governor characteristiccurve may be changed to conform to the characteristic curve of agenerator by varying the proportionate values of the current flowing inthe governor armature and the generator armature, and

Fig. 8 is a diagram showing the governor connected to a generator.

The torque governor illustrated simulates a motor, the windings 22 beingstationary,

similar to the field windings of a motor, while the windings 23 arecarried by a rotor. Since it is not required, in the functioning of atorque governor of this type, that the rotor rotate through 360 or more,it is sufficient to provide flexible conductors, such as 24:, forconnecting the winnings 23 carried by the rotor in the proper circuits.Therefore, on account of the absence of brushesfthe resistance offeredby bearing surfaces to the rota tion of the rotor may be reduced to avalue that is negligible, and the governor may be made extremelysensitive to variations in torque. V

In order to utilize the governor for the controlling of electricalcircuits, a contact-carrying arm 25 is adjustably mounted on a plate 26which is keyed to the shaft 27 of the rotor provided to carry thewindings 23. The plate 26 is provided with a plurality of openings 28which are arranged in a circle near its periphery. The contact-carryingarm 25 is provided with two groups of openings 29 which are disposeddiametrically opposite each other and are positioned to aline with theopenings 28 provided in the plate 26.

As will be noted, the angular spacing of the openings 29 in thecontact-carrying arm 25 is not the same as the spacing of the openings28 in the plate 26. Therefore, in order to aline one of the openings29with an opening 28, it is not required that the plate andcontact-carrying arm 25 shall be adjusted relative to one anotherthrough an angle equal to the angular spacing of the openings, anadjustment of the plate 26 through an angle equal to a fraction of theangular spacing of the openings being sufiicient. Therefore, provisionis made for effecting a micrometer adjustment of the contact-carryingarm relative to the plate 26.

When the contact-carrying arm has been set in any predetermined positionrelative to the plate 26, it may be retained in that posi-- tion by anysuitable means, such as screws 30. In this construction, when one of theopenings 29 is alined with one of the openings 28, an opening of hediametrically opposite group of openings 29 will be alined with anotheropening 28. However, this is a matter of design and not essential.

In the manner described above, the contact-carrying arm 25 may be set indifferent predetermined posit-ions relative to the plate 26 and to thewindings 23 carried by the rotor, which herienafter will be referred toas the rotor. A contact membe 31 is mounted on the contact-carrying arm25.

As best shown in Fig. 2, the contact menber 31 is disposed between twoadjustably mounted contact screws 32 and 33 which are carried by abracket 34 that is mounted on the governor frame. In this particularconstruction, the contact member 31 is disposed to engage only thecontact screw 33, an insulating block 35 being interposed between thecontact member 31 and the contact screw 32. In this construction, thecontact screw is utilized as a stop to limit the angular movement of thearm 25.

Ihe contact member 31 may be connected in any electrical circuit bymeans of the screw 36, while any conductor may be directly connected tothe screw 33. Since the contact screws 32 and 33 are adjustable,provision is' made to change, as desired, the limits of movement of thecontact member In order to electrically connect the conductors 24' intoa circuit, terminal posts 37 are provided. The field of the governor, orthe windings 22, may be electrically connected to any circuit by meansof the terminal posts It will be readily understood that any desirednumber of terminal posts 37 and 38, with the desired number of turns ofthe rotor or field windings connected bemay be utilized for adapting todiif rent service conditions.

the governor must be carefully ZLAjUSId such features will have theirlimitations, and it will generally be required that the governor shallbe designed to meet the particular conditions under which it is to beutilized for controlling the torque on ti o engine.

Leferring again to Fig. 2, a tensioning lever 39 is shown rotatablymounted on a laterally extending rim 40 provided on the governor frame.Tension springs ll are connectedbetween the tensioning lever 39 and thecontact-carrying arm 25. In order to retain the tensioning lever 39 indifferent positions, a ratchet a2 is provided on the governor frame toengage a dog disposed on the under side of the lever handle 43.

The governor may be connected in a generator circuit in the manner shownand described in my co-pending application hereinbefore referred to.However, in order that this application may be substantially complete initself, the connection of the governor in a generator circuit is shownin Fig. 7.

As will be observee, the governor field winning is connected in serieswith the genera'tor field winding, while the governor armature isdisposed to shunt the interpole field winding of the generator. However,any other suitable connections between the generator and torque governormay be made.

The characteristic curve of the torque govenor' will depend on itsstructural and electrical features. However, by varying the currentflowing in the governor windings, making the proper adjustments of therotor and tensioning lever 43, the characteristic curve of the governormay be made to coincide with or match substantially any selectedgenerator curve.

In order to explain clearly the manner of the gover u flower sin ce ispeed of 750 R. P. M.

adjusting a governor to match its character istic curve with that of agenerator, a set of curves is submitted showing a plurality of generatorcurves and the effect on the governor curve of varying the current inthe governor windings and of making adjustments of the governor parts.

The typical generator curves illustrated in Fig. lwere obtained from twogenerators of differenttypes by plotting values of field current andarmature current corresponding to constant torque. The curve designatedS was obtained from a compensated generator, while the curve R is acharacteristic curve of a 210 kw. generator having a rated Referring toFig. 5, two torque-governor characteristic curves, which extendsubstantially parallel to each other, are shown. These curves wereobtained by plotting the iield amperes on the values of generatorarmature current at which the governor functioned.

In making the test to obtain the current values from which the curve 4awas obtained, :he torque-governor armature windings were connected inshunt with the interpole field windings which normally carry the fullcurrent of the generator-armature windings and adjusted to carry 1% ofthe generator-arma ture amperes, while the torque-governor fieldwindings and generator field windings were connected in series. Further,the tensioning lever 43 was set to give maximum spring ten sion.

Each point on the curve 44 was determined by applying power to thegovernor and observing values of field and armature current at which thegovernor would function. The curve 45 was obtained in the same way aswas curve 44:, with the exception that the tension of the spring 41 wasweakened. The result of weanening the spring tension, as shown in Fig.5, was to effect a shifting of the curve along an axis extending at anangle of 45 from the horizontal.

Therefore, it will be seen that, when it is desired to change thetorque-governor curve to match a particular generator curve, it may bemoved substantially parallel to itself by adjusting the tension of thegovernor springs 41 to reduce or increase the output of the generator,and, consequently, of the internalcombustion engine.

The curve shown in Fig. 6 illustrates how the characteristic torquegovernor may be changed by setting the governor armature in differentpositions relative to the field windings. In making the test, a neutralposition for the governor armature is assumed, and the values of thefield and armature current at which the governor functions were plotted,giving the curve 46.

ssurning now that the governor armature is rotated 10 clockwise or inthe forward direction, a magnetizing effect is produced that is due tothe armature current, which permits the functioning of the governor onthe flow of a smaller amount of current in the field winding than isrequired when the governor armature stands in the neutral position. Infact, it has been found that the governor will operate in response to havy armature currents and without any field current. Accord ingly, thecurve 47, plotted from the field and armature current values obtainedwith the governor armature set 10 forward from neutral, is distorteddownwardly.

When the governor armature is rotated backwardly or counter-cloclnvisewith respect to the field to give it a back-lead relative to the assumedneutral position, a demagnetiziug action is effected by the armaturecurrent. Therefore, before the governor functions, it is required thatthe current flowing in the field windings be increased above the valuesrequired to etiiec't an operation of the governor when it stands in itsneutral p sition.

The curve was obtained from the current values read when the governorarmature was set counter-clockwise 15.

The our s 50 and 51 were obtained by varying t e proportionate value ofthe cur rents flow in the governor armature and the generator armature.As illustrated in Fig. 8, the torque-governor armature 52 is connectedto shunt the interpole winding 53 the generator 54:, and a rheostat 55is provided for varying the proportionate values of the current flowingin the torque-governor armature and in the generator armature.

Assuming now that the rheostat 55 is adusted to permit 1% of thegenerator current to flow through the torquegovernor armature, byplotting the fieid-current amperes on the generator-arma'ure amperes,the curve 49 is obtained. If the amount of current fiowing in thetorque-governor armature is decreased, the curve will be distortedupwardly, as shown by the curve 50, while, if the percentage ofcurrentfiowing in the torque go ernor armature is increased, the curveis dis torted downwardly, see curve 51). The current values for plottingthe curves 50 and 51 were obtained when the current fiowing in thetorquegovernor armature was made 8% and 1.2%, respectively, of thecurrent flowing in the generator armature.

It will, therefore, be evident that the torque governor may be adjustedto meet different operating conditions in three ways; i. e., by rotatingthe rotor clockwise or counter-clockwise relative to the field windingsby varying the ratio between the current flowing in the generatorarmature and the torque-governor armature, and by shifting the lever 43to vary the tension of the springs l1. Further, if

necessary, the torque governor may be specially designed to adapt it tobe utilized with selected types or generators.

Since numerous changes may be made in the above-described construction,and differant embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a torque governor provided with field windings and a rotatablearmature, in combination, a switch carried by the armature, resilientmeans disposed to bias the armature in a predetermined angulardirection, said switchbeing disposed to be closed by the biasing forcedelivered through the armature and means for adjusting said switchrelative to the armature.

2. In a torque governor provided with a field winding and a rotatablearmature winding, in combination, a contact member carried by thearmature and Vernier adjusting device interposed between the contactmember and the armature.

3. In a torque governor provided with a field winding and a rotatablearmature winding, in combination, a contact member carried by thearmature winding, a Vernier adjustment interposed between the contactmember and armature winding and resilient means for biasing the armatureto a predetermined position said position being determined by theposition of the contact member relative to the armature windin 4:. In atorque governor provided with field and armature windings, incombination, means for biasing the armature to different predeterminedrelative positions with respect to the field windings, and terminalconnectors connected in the field and armature windings to providesections that may be connected in any circuit.

5. In a torque governor provided with a field winding and a rotatablearmature, in combination, a contact member carried by the armature and astationary contact member disposed to receive the armature contactmember, means for biasing the contact members into engagement and meansfor connecting predetermined sections or" the field and armaturewindings to carry electric currents to adapt the governor to differentoperating conditions.

6. In a torque governor provided with a field winding and a rotatablearmature, in combination, means for connecting different sections of thefield and armature windings to carry electric currents to adapt thegovernor to different operating conditions, a contact member adjustablymounted on the armature, a stationary contact member to stop thearmature in difi'erent predetermined positions, resilient means forbiasing the contactmembers into engagement and means for varying theforce exerted by said resilient means to change the operating characteristics of the governor.

7. In a torque governor provided with relatively movable field andarmature windings, in combination, a switch disposed to be actuated uponthe relative movement of the governor windings, means disposed to biasthe armature in a predetermined angular direction, a switch disposed tobe actuated upon movement of the armature in a predetermined directionand means for adjusting said switch to adapt itto diil erent relativemovements of the governor windings.

8. In a torque governor, in combination,

field and armature windings, said armature being rotatably mounted, acontact member adjustably mounted on the armature, a stationary contactmember disposed to receive he armature contact member and resilient sfor biasing the armature in a predetermined direction to set the contactmembers in predetermined relative positions.

9. In a torque governor provided with field and armature windings, incombination, means for setting the armature windings in differentpredetermined positions relative to the field windin s, resilient meansfor biasing the armature windings to said predetermined positions, aswitch disposed to'be actuated upon the relative movement of the fieldarmature windings, the switch being biased to its closed position bysaid resilient means, and means for limiting the movement of the switch.

10. In a torque governor provided with relatively movable field andarmature wind ings, in combination, means for setting the armaturewindings in different predetermined positions relative" to the fieldwindings, and resilient means for biasing the armature in saidpredetermined positions, said resilient biasing means being adjustableto vary the biasing force, said armaturesetting means and said means forvarying the biasing force being cooperative to change the operatingcharacterstics of the governor, thereby to change the characteristiccurve obtained by plotting values of field current on armature current.

11. In a torque governor provided with relatively movable fieldand'armature windings, in combination,means for setting the armaturewindings in difierent predetermined positions relative to the fieldwindings, resilient means for biasing the armature windings to saidpredetermined positions, said resilient means being adjustable to varythe biasing force and means for controlling the current flowing in thefield and armature windings of the governor, said means for setting thearmature and field windings in different relative positions, the

means for varying the biasing force and the means for controlling thecurrent in the field and armature windings being cooperative to changethe operating characteristics of the governor, thereby to change thecharacter istic curve of the governor obtained by plotting values offield current on armature current.

12. In combination, a generator provided with field and armaturewindings, a torque governor provided with relatively movable field andarmature windings, the field and armature windings of the torquegovernor being connected in series with the field and armature windingsof the generator, respectively, means for setting the armature windingsand the torque governor in difierent positions relative to the fieldwindings, resilient means for biasing the armature windings of thetorque governor to said predetermined positions, said resilient meansbeing adjustable to vary the biasing force, means for controlling theratio of current flowing in the field and armature windings of thetorque governor in different predetermined positions relative to thefield windings, the means for varying the biasing force and the meansfor varying the ratio of the current in the field and armature windingsbeing cooperativ to 39 change the characteristic curve of the torquegovernor obtained by plotting field amperes on armature amperes in orderto match the characteristic curve of the generator.

13. In a torque governor provided wit-h relatively movable field andarmature windings, in combination, resilient means for biasing thearmature and field windings to different predetermined relativepositions, said resilient means being adjustable to vary 40 the biasingforce, and means for controlling the ratio of current in the field andarmature windings, said means for varying the biasing force and meansfor controlling the ratio of current being cooperative to change theoperating characteristics of the torque governor to change thecharacteristic curve obtained by plotting values of field current onarmature current.

14. In a torque governor, in combination, stationary field windings, arotor disposed for movement relative to the field windings,

armature windings provided on the rotor, a

switching member carried by the rotor,

means cooperative with the switching member to to limit the angularmovement of the rotor in one direction and means for setting theswitching member in difierent predetermined angular positions relativeto the rotor to change the characteristic curve of the gov- CG ernorobtained by plotting field current on armature current.

In testimony whereof, I have hereunto subscribed my name this 8th day ofOctober, 1927.

NORMAN WV. STORER.

